Hecht S M, Frye R B, Werner D, Fukui T, Hawrelak S D
Biochemistry. 1976 Mar 9;15(5):1005-15. doi: 10.1021/bi00650a010.
The 6-aza analogues of toyocamycin and sangivamycin were prepared as potential cytotoxic agents. The toyocamycin analogue (4-amino-1-(beta-D-ribofuranosyl)pyrazolo[3,4-d]pyrimidine-3-carbonitrile) could not be obtained directly from its O-acetylated precursor but was accessible via 4-amino-1-(beta-D-ribofuranosyl)pyrazolo[3,4-d]pyrimidine-3-thiocarboxamide. The identity of the nitrile was verified by its ultraviolet, infrared, and mass spectra, and by its conversion to the corresponding 3-carboxamide and thiocarboxamide when treated with water or hydrogen sulfide, respectively. Bioassay of the synthetic compounds in comparison with 4-amino-1-(beta-D-ribofuranosyl)pyrazolo[3,4-d]pyrimidine (6-azatubercidin) and 4-amino-2-(beta-D-ribofuranosyl)pyrazolo[3,4-d]pyrimidine revealed that the 3-thiocarboxamido derivative was more cytotoxic to the growth of mouse fibroblasts than 6-azatubercidin, effecting killing of 3T6 cells at less than or equal to 1 mug/ml. 4-Amino-1-(beta-D-ribofuranosyl)pyrazolo[3,4-d]pyrimidine (but not its 2-ribofuranosyl isomer) was shown to act as a substrate for adenosine deaminase from calf intestinal mucosa with an apparent Km of 125 (vs. 20 for adenosine) and the corresponding 5'-diphosphate of 6-azatubercidin was polymerized by polynucleotide phosphorylase (Micrococcus luteus) in the presence of Mn2+ to afford a homopolymer and copolymers with adenosine. The copolymers directed the binding of [3H]lysyl-tRNA to the A-site of ribosomes from Escherichia coli, but could not be used for the synthesis of polylsine in a cellfree system. The copolymer consiting of adenosine and 6-azatubercidin in a 2:1 ratio was found to form a 1:1 complex with poly(uridylic acid) at 4degreesC.
制备了丰加霉素和偏端霉素的6-氮杂类似物作为潜在的细胞毒性剂。丰加霉素类似物（4-氨基-1-(β-D-呋喃核糖基)吡唑并[3,4-d]嘧啶-3-腈）不能直接从其O-乙酰化前体获得，但可通过4-氨基-1-(β-D-呋喃核糖基)吡唑并[3,4-d]嘧啶-3-硫代甲酰胺得到。腈的结构通过其紫外光谱、红外光谱和质谱以及分别用水或硫化氢处理时转化为相应的3-甲酰胺和硫代甲酰胺得以证实。将合成化合物与4-氨基-1-(β-D-呋喃核糖基)吡唑并[3,4-d]嘧啶（6-氮杂结核菌素）和4-氨基-2-(β-D-呋喃核糖基)吡唑并[3,4-d]嘧啶进行生物测定，结果表明3-硫代甲酰胺基衍生物对小鼠成纤维细胞生长的细胞毒性比6-氮杂结核菌素更强，在浓度小于或等于1微克/毫升时就能杀死NIH 3T6细胞。4-氨基-1-(β-D-呋喃核糖基)吡唑并[3,4-d]嘧啶（而非其2-呋喃核糖基异构体）被证明是来自小牛肠黏膜的腺苷脱氨酶的底物，其表观米氏常数为125（腺苷的米氏常数为20）[13]，并且在Mn2+存在下，6-氮杂结核菌素的相应5'-二磷酸被多核苷酸磷酸化酶（藤黄微球菌）聚合得到均聚物以及与腺苷的共聚物。这些共聚物引导[3H]赖氨酰-tRNA与大肠杆菌核糖体的A位点结合，但在无细胞系统中不能用于合成聚赖氨酸。发现腺苷和6-氮杂结核菌素以2:1比例组成的共聚物在4℃时与聚（尿苷酸）形成1:1复合物。
